python-build: add build prerequisite installer

.github/actions/build-python/action.yml

@@ -9,6 +9,12 @@ inputs:
 runs:
   using: composite
   steps:
+    - shell: bash
+      run: |
+        #envvars
+        export PYENV_ROOT="$GITHUB_WORKSPACE"
+        echo "PYENV_ROOT=$PYENV_ROOT" >> $GITHUB_ENV
+        echo "$PYENV_ROOT/shims:$PYENV_ROOT/bin" >> $GITHUB_PATH
     # The two OSes differ only in this step.
     - if: runner.os == 'macOS'
       shell: bash
@@ -19,15 +25,7 @@ runs:
       shell: bash
       run: |
         #prerequisites
-        sudo apt-get update -q; sudo apt install -yq make build-essential libssl-dev zlib1g-dev \
-        libbz2-dev libreadline-dev libsqlite3-dev curl \
-        libncursesw5-dev xz-utils tk-dev libxml2-dev libxmlsec1-dev libffi-dev liblzma-dev
-    - shell: bash
-      run: |
-        #envvars
-        export PYENV_ROOT="$GITHUB_WORKSPACE"
-        echo "PYENV_ROOT=$PYENV_ROOT" >> $GITHUB_ENV
-        echo "$PYENV_ROOT/shims:$PYENV_ROOT/bin" >> $GITHUB_PATH
+        pyenv install-prerequisites
     - shell: bash
       run: |
         #build

.github/workflows/modified_scripts_build.yml

@@ -220,10 +220,7 @@ jobs:
           echo "$PYENV_ROOT/shims:$PYENV_ROOT/bin" >> $GITHUB_PATH
       - run: |
           #prerequisites
-          sudo apt-get update -q; sudo apt-get install -yq make build-essential \
-            libssl-dev zlib1g-dev libbz2-dev libreadline-dev libsqlite3-dev \
-            curl llvm libncurses5-dev libncursesw5-dev \
-            xz-utils tk-dev libffi-dev liblzma-dev
+          pyenv install-prerequisites
           if [[ "${{ matrix.python-version }}" =~ pypy.*-(src|dev) ]]; then
             export PYENV_BOOTSTRAP_VERSION=pypy2.7-7
             echo "PYENV_BOOTSTRAP_VERSION=$PYENV_BOOTSTRAP_VERSION" >> $GITHUB_ENV
@@ -283,10 +280,7 @@ jobs:
           echo "_PYTHON_BUILD_FORCE_SKIP_XZ=1" >> $GITHUB_ENV
       - run: |
           #prerequisites
-          sudo apt-get update -q; sudo apt-get install -yq make build-essential \
-            libssl-dev zlib1g-dev libbz2-dev libreadline-dev libsqlite3-dev \
-            curl libncursesw5-dev \
-            xz-utils tk-dev libffi-dev liblzma-dev
+          pyenv install-prerequisites
       - run: |
           #build
           pyenv --debug install ${{ matrix.python-version }} && rc=$? || rc=$?

plugins/python-build/README.md

@@ -54,8 +54,11 @@ Or, if you would like to install the latest development release:
 
 ## Usage
 
-Before you begin, you should ensure that your build environment has the proper
-system dependencies for compiling the wanted Python Version (see our [recommendations](https://github.com/pyenv/pyenv/wiki#suggested-build-environment)).
+On Ubuntu, Debian, and Mint, install the recommended build dependencies with:
+
+    pyenv install-prerequisites
+
+For other environments, see our [build environment recommendations](https://github.com/pyenv/pyenv/wiki#suggested-build-environment).
 
 ### Using `pyenv install` with pyenv
 
@@ -361,4 +364,3 @@ git diff --name-only master \
 - Filter out any which don't live where python-build keeps its build scripts
 - Look only at the file name (i.e. the python version name)
 - Run a new docker container for each, building that version
-

plugins/python-build/bin/pyenv-install-prerequisites

@@ -0,0 +1,46 @@
+#!/usr/bin/env bash
+#
+# Summary: Install Python build prerequisites on Debian-based systems
+#
+# Usage: pyenv install-prerequisites
+#
+set -e
+[ -n "$PYENV_DEBUG" ] && set -x
+
+if [ "$1" = "--complete" ]; then
+  exit
+fi
+
+usage() {
+  pyenv-help install-prerequisites 2>/dev/null
+  [ -z "$1" ] || exit "$1"
+}
+
+if [ "$1" = "-h" ] || [ "$1" = "--help" ]; then
+  usage 0
+fi
+
+[ "$#" -eq 0 ] || usage 1 >&2
+
+if ! command -v apt-get >/dev/null; then
+  echo "pyenv: installing build prerequisites is not supported on this system" >&2
+  exit 1
+fi
+
+prerequisites=(
+  make build-essential libssl-dev zlib1g-dev libbz2-dev libreadline-dev
+  libsqlite3-dev curl git llvm libncurses5-dev libncursesw5-dev xz-utils
+  tk-dev libxml2-dev libxmlsec1-dev libffi-dev liblzma-dev libzstd-dev
+)
+
+if [ "$(id -u)" -eq 0 ]; then
+  apt_get=(apt-get)
+elif command -v sudo >/dev/null; then
+  apt_get=(sudo apt-get)
+else
+  echo "pyenv: sudo is required to install build prerequisites" >&2
+  exit 1
+fi
+
+"${apt_get[@]}" update -q
+"${apt_get[@]}" install -yq "${prerequisites[@]}"

plugins/python-build/test/install-prerequisites.bats

@@ -0,0 +1,82 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+_setup() {
+  prerequisites="make build-essential libssl-dev zlib1g-dev libbz2-dev \
+libreadline-dev libsqlite3-dev curl git llvm libncurses5-dev \
+libncursesw5-dev xz-utils tk-dev libxml2-dev libxmlsec1-dev libffi-dev \
+liblzma-dev libzstd-dev"
+}
+
+@test "completion does not install packages" {
+  stub apt-get
+
+  run pyenv-install-prerequisites --complete
+
+  assert_success
+  unstub apt-get
+}
+
+@test "supports help" {
+  stub pyenv-help 'install-prerequisites : echo "Usage: pyenv install-prerequisites"'
+
+  run pyenv-install-prerequisites --help
+
+  assert_success "Usage: pyenv install-prerequisites"
+  unstub pyenv-help
+}
+
+@test "rejects arguments" {
+  stub pyenv-help 'install-prerequisites : echo "Usage: pyenv install-prerequisites"'
+
+  run pyenv-install-prerequisites unexpected
+
+  assert_failure "Usage: pyenv install-prerequisites"
+  unstub pyenv-help
+}
+
+@test "installs build prerequisites with apt-get as root" {
+  stub id '-u : echo 0'
+  stub apt-get \
+    'update -q : true' \
+    "install -yq ${prerequisites} : true"
+
+  run pyenv-install-prerequisites
+
+  assert_success
+  unstub apt-get
+  unstub id
+}
+
+@test "uses sudo when not running as root" {
+  stub id '-u : echo 1000'
+  stub apt-get
+  stub sudo \
+    'apt-get update -q : true' \
+    "apt-get install -yq ${prerequisites} : true"
+
+  run pyenv-install-prerequisites
+
+  assert_success
+  unstub sudo
+  unstub apt-get
+  unstub id
+}
+
+@test "fails when apt-get is unavailable" {
+  PATH="$(path_without apt-get)" run pyenv-install-prerequisites
+
+  assert_failure "pyenv: installing build prerequisites is not supported on this system"
+}
+
+@test "fails when sudo is unavailable for an unprivileged user" {
+  stub id '-u : echo 1000'
+  stub apt-get
+
+  PATH="$(path_without sudo)" run pyenv-install-prerequisites
+
+  assert_failure "pyenv: sudo is required to install build prerequisites"
+  unstub apt-get
+  unstub id
+}